IPAC2013 - List of Authors (Yano, Y.)

Paper	Title	Page
THPWO038	Electron Stripping of High-intensity ²³⁸U Ion Beam with Recirculating He Gas	3851
	H. Imao RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan T. Dantsuka, M. Fujimaki, N. Fukunishi, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, K. Kumagai, T. Maie, H. Okuno, T. Watanabe, Y. Watanabe, K. Yamada, Y. Yano RIKEN Nishina Center, Wako, Japan
	Next-generation in-flight RI beam facilities such as RIBF and FRIB pursue powerful and energetic ²³⁸U ion beams to produce thousands of new isotopes. For their efficient acceleration, a durable electron stripper in the intermediate energy region around 10-20 MeV/u is indispensable. However, there is no available stripper for the U beams with the intensity of more than 1 puA so far because of the lifetime problem of thin solid strippers caused by high energy loss. 　In the present study, a novel electron stripping system employing high-flow rate He gas circulation (200 L/min) has been developed. He gas with the thickness of 0.6 mg/cm² is confined and separated from beamline vacuum using five-stage differentially-pumped sections. To avoid huge gas consumption, a clean gas recycling is achieved with multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99%. The system was successfully operated in user runs with U³⁵⁺ beams more than 1 puA injected at 10.8 MeV/u for the first time. U⁶⁴⁺ beams were stably delivered to subsequent accelerators with the stripping efficiency of 23% without any deterioration of the system.

Paper

Title

Page

Electron Stripping of High-intensity ²³⁸U Ion Beam with Recirculating He Gas

3851

H. Imao
RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
T. Dantsuka, M. Fujimaki, N. Fukunishi, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, K. Kumagai, T. Maie, H. Okuno, T. Watanabe, Y. Watanabe, K. Yamada, Y. Yano
RIKEN Nishina Center, Wako, Japan

Next-generation in-flight RI beam facilities such as RIBF and FRIB pursue powerful and energetic ²³⁸U ion beams to produce thousands of new isotopes. For their efficient acceleration, a durable electron stripper in the intermediate energy region around 10-20 MeV/u is indispensable. However, there is no available stripper for the U beams with the intensity of more than 1 puA so far because of the lifetime problem of thin solid strippers caused by high energy loss. 　In the present study, a novel electron stripping system employing high-flow rate He gas circulation (200 L/min) has been developed. He gas with the thickness of 0.6 mg/cm² is confined and separated from beamline vacuum using five-stage differentially-pumped sections. To avoid huge gas consumption, a clean gas recycling is achieved with multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99%. The system was successfully operated in user runs with U³⁵⁺ beams more than 1 puA injected at 10.8 MeV/u for the first time. U⁶⁴⁺ beams were stably delivered to subsequent accelerators with the stripping efficiency of 23% without any deterioration of the system.